JP5850153B2 - Mapping relationship establishment method, channel quality information feedback method, and apparatus - Google Patents

Description

  The present invention relates to a transmission technology in a wireless communication system, and more particularly to a mapping relationship establishment method, channel quality information feedback method, and apparatus.

  In enhanced long term evolution (LTE-Advanced: Long Term Evolution-Advanced) systems, coordinated multi-point (CoMP) transmission is gaining wide attention in order to improve the throughput of user equipment at the edge of a cell. As shown in FIG. 1 (a), different transmission points in the same cell may transmit in a coordinated manner, or as shown in FIG. 1 (b), different transmission points in different cells transmit in a coordinated manner. May be.

  In order to select the optimal coordinated transmission point, the base station needs to acquire downlink channel information to the user of each transmission point and select one or more optimal transmission points according to specific optimization rules. is there. Usually, the downlink channel information includes channel quality information (CQI), precoding matrix index (PMI), and rank. In order to ensure backward compatibility and more flexible scheduling, the base station needs to have the ability to fall back to a single point transmission of a conventional cellular network. For this reason, when the user feeds back downlink channel information, it is necessary to report not only downlink channel information in cooperative multipoint transmission but also downlink channel information in conventional single point transmission.

  The CoMP technology is divided into two types: multipoint joint processing (JP: Joint Processing) and multipoint coordinated scheduling / beamforming (CS / CB: Coordinated Scheduling / Beamforming). Although user feedback information differs depending on different CoMP techniques, it is necessary to feed back CQI in conventional single point (NoN-CoMP, non-CoMP) communication and CQI in multipoint coordinated (CoMP) transmission.

Here, for JP transmission, the received signal is expressed by Equation (1).

は、ＪＰ送信において協調送信点ｂが用いるプリコーディングマトリックスであり、

は、協調送信点ｂからユーザ機器へのチャネルであり、

は、送信データであり、

は、ノイズである。ユーザ機器は、各送信点のプリーコーディングマトリックス

をフィードバックし、報告に基づくプリーコーディングマトリックス、及び式（１）に対応する量子化された信号対雑音比、即ちＣＱＩをフィードバックする。また、ユーザ機器は、単一ポイント送信のみのＣＱＩ、即ち式（２）で表される量子化された信号対雑音比をフィードバックする必要もある。

Of which

Is a precoding matrix used by the cooperative transmission point b in JP transmission,

Is a channel from the cooperative transmission point b to the user equipment,

Is the transmitted data,

Is noise. The user equipment has a precoding matrix for each transmission point.

And a quantized signal-to-noise ratio corresponding to Equation (1), ie, CQI, is fed back. The user equipment also needs to feed back the CQI for single point transmission only, that is, the quantized signal-to-noise ratio expressed by Equation (2).

According to the standard definition of LTE / LTE-Advanced, the CQI fed back aperiodically by the conventional single point transmission by the user equipment is the first transport block (TB) as shown in Table 1. And / or the 2nd TB is displayed with 4 bits, and the CQI periodically fed back by the user equipment by the conventional single point transmission is as shown in Table 1, the 1st TB is 4 bits. As shown in Table 2, the second TB is displayed in 3 bits, where the difference CQI between the second TB and the first TB, that is, the offset of the second TB = 1st TB CQI index of the second-CQI index of the second TB. Here, the numerical values 0, 1, 2, 3, -4, -3, -2, and -1 in the offset column of Table 2 are preset offset reference values for comparison with the calculated offset. Based on the calculated offset, Table 2 is collated and compared with the offset reference value in Table 2 to obtain the corresponding difference CQI value. For example, as shown in Table 2, when the calculated offset is 4, the corresponding difference CQI is 3, and when the calculated offset is 2, the corresponding difference CQI is 2, and the calculated offset is −5. In this case, the corresponding difference CQI is 4, which can be estimated by this.

  However, in CoMP transmission, it is necessary to feed back not only the CQI of single point transmission but also the CQI of CoMP transmission, which increases the feedback overhead, and the physical uplink control channel (PUCCH) or physical uplink control channel (PUCCH) The efficiency of the uplink shared channel (PUSCH) decreases. In order to efficiently transmit PUCCH / PUSCH user equipment feedback information, it is a problem to design CQI feedback in CoMP transmission considering the characteristics of cooperative multipoint transmission.

  It should be noted that the above description relating to the prior art is merely for explaining the technical solution of the present invention more clearly and completely, and is intended to allow those skilled in the art to understand. Since these technical solutions are described in the background section of the present invention, they should not be construed as techniques well known to those skilled in the art.

  Embodiments of the present invention can improve the overhead of user equipment through CoMP transmission, and reduce the overhead of CQI feedback by designing rational CQI feedback for different performance improvements by different CoMP transmission technologies. It is an object of the present invention to provide a method for establishing a mapping relationship between a differential CQI and an offset, a method for feedback of channel quality information used in a cooperative multipoint system, and an apparatus.

  According to one aspect of an embodiment of the present invention, there is provided a method for establishing a mapping relationship between a differential CQI and an offset, wherein a terminal device maps each bit value of channel quality information (CQI) to an offset reference value. Determining the number of bits indicating the differential CQI and the mapping relationship in a coordinated multipoint (CoMP) transmission mode so that the differential CQI is fed back based on the mapping relationship. A plurality of offset reference values corresponding to the bit values are a plurality of increasing integers, and provide a mapping relationship establishing method.

  According to another aspect of the embodiment of the present invention, the number of bits indicating the differential CQI in the CoMP transmission mode and the feedback of the differential CQI based on the mapping relationship between each bit value of the differential CQI and the offset reference value, and The terminal device includes an establishing means for determining the mapping relationship, wherein the plurality of offset reference values corresponding to the bit values in ascending order of the bit values are a plurality of increasing integers.

  According to another aspect of an embodiment of the present invention, there is provided a CQI feedback method used for a terminal device set in a cooperative multipoint (CoMP) feedback mode, wherein non-CoMP transmission is performed based on a downlink reference signal. Calculating a CQI offset based on CoMP transmission based on CQI based on non-CoMP transmission and CQI based on CoMP transmission; 2 and a determination step of determining a differential CQI based on CoMP transmission based on a mapping relationship between a CQI offset based on the CoMP transmission and a differential CQI and offset established in advance. Mapping relationship between differential CQI and offset The plurality of offset reference values corresponding to the difference CQI in order of increasing difference CQI are a plurality of increasing integers, and the base station calculates the CQI based on the non-CoMP transmission and the difference CQI based on the CoMP transmission. And providing a feedback method of channel quality information.

  According to another aspect of the embodiment of the present invention, a terminal device configured in a CoMP feedback mode calculates CQI based on non-CoMP transmission and CQI based on CoMP transmission based on a downlink reference signal. First calculation means; second calculation means for calculating CQI offset based on CoMP transmission based on CQI based on non-CoMP transmission calculated by said first calculation means and CQI based on CoMP transmission; and Determining means for determining a differential CQI based on CoMP transmission based on a CQI offset calculated based on the CoMP transmission calculated by the second calculating means and a mapping relationship between the differential CQI and the offset established in advance; In the mapping relationship between the established differential CQI and offset, the differential CQI is small. The plurality of offset reference values corresponding to the differential CQI are a plurality of increasing integers, CQI based on non-CoMP transmission calculated by the first calculation unit, and CoMP determined by the determination unit Feedback means for feeding back a differential CQI based on transmission to a base station is provided.

  According to another aspect of the embodiment of the present invention, when executing a program in a terminal device, the computer causes the terminal device to execute the above-described method for establishing the mapping relationship between the differential CQI and the offset. Provide a program.

  According to another aspect of the embodiment of the present invention, there is provided a storage medium for storing a computer-readable program for causing a computer to execute the above-described method for establishing a mapping relationship between differential CQI and offset in a terminal device. .

  According to another aspect of the embodiment of the present invention, there is provided a computer-readable program for causing a computer to execute the above-described channel quality information feedback method in the terminal device when the program is executed in the terminal device.

  According to another aspect of an embodiment of the present invention, there is provided a storage medium for storing a computer-readable program for causing a computer to execute the above-described channel quality information feedback method in a terminal device.

  As a beneficial effect of the embodiments of the present invention, it is possible to reduce the overhead of CQI feedback by designing rational CQI feedback with respect to different performance improvements by different CoMP transmission technologies, and user equipment based on CoMP transmission. Throughput can be improved.

  As shown in the following description and drawings, specific embodiments of the present invention are disclosed in detail and show the manner in which the principles of the invention can be employed. The scope of the embodiment of the present invention is not limited to these. The embodiments of the present invention include changes, modifications and equivalents within the spirit and scope of the appended claims.

  Features described and / or illustrated features in one embodiment may be used in one or more other embodiments in the same or similar manner, and may be combined with features in other embodiments. It may replace the feature in other embodiments.

  In this context, the term “inclusive / include / have” refers to the presence of a feature, member, step or component and does not exclude the presence or addition of one or more other features, members, steps or components. .

Many aspects of the invention can be understood with reference to the following drawings. Elements in the drawings are not drawn to scale but are for illustrating the principles of the invention. Corresponding parts in the drawings may be enlarged or reduced in order to show or describe a part of the invention. Elements and features described in one drawing and one embodiment of the invention may be combined with elements and features shown in one or more drawings or embodiments. In the drawings, like numerals indicate corresponding elements in the drawings, and may indicate corresponding elements used in one or more embodiments.
(A) is a figure which shows the cooperation multipoint of the same cell in the scenario of cooperation multipoint transmission. (B) is a figure which shows the cooperation multipoint of a different cell in the scenario of cooperation multipoint transmission. 7 is a flowchart of a method for establishing a mapping relationship between a differential CQI and an offset according to an embodiment of the present invention. It is a figure which shows the structure of the terminal device which concerns on the Example of this invention. 5 is a flowchart of a channel quality information feedback method according to an embodiment of the present invention. It is a figure which shows the structure of the other terminal device which concerns on the Example of this invention.

  The foregoing and other features of the embodiments of the present invention can be understood through the following specification with reference to the drawings. These embodiments are merely illustrative and do not limit the invention. As those skilled in the art will better understand the principles and embodiments of the present invention, the embodiments of the present invention are based on cooperative multipoint (CoMP) transmission (including JP transmission and CS / CB transmission) of an LTE-Advanced system. However, the embodiments of the present invention are not limited to the above system and the above transmission method, and can be applied to other systems and other transmission methods related to cooperative multipoint transmission. Further, in the following description, the “base station” refers to a transmission point for coordinated multipoint transmission, and may be, for example, a normal eNB (evolved Node B) or RRH (Remote Radio Head). : Remote radio head), and the present embodiment is not limited to this.

<Example 1>
FIG. 2 is a flowchart of a method for establishing a mapping relationship between a differential CQI and an offset according to an embodiment of the present invention. As shown in FIG. 2, the method includes the following steps.

  Step 201: The terminal apparatus indicates the differential CQI in the coordinated multipoint (CoMP) transmission mode so that the differential CQI is fed back based on the mapping relationship between each bit value of the channel quality information (CQI) and the offset reference value. The number of bits and the mapping relationship are determined.

  Here, in the mapping relationship, the plurality of offset reference values corresponding to the bit values in ascending order of the bit values are a plurality of increasing integers.

  After establishing the mapping relationship between the differential CQI and the offset by the method of the present embodiment, the terminal apparatus can perform feedback of the differential CQI based on the relationship. For example, when it is necessary for the terminal device to feed back the differential CQI, the calculated offset is compared with the offset reference value in the mapping relationship established according to the present embodiment, and the corresponding differential CQI is determined and fed back. can do.

In one embodiment, the mapping relationship between the differential CQI and the offset may be stored in the form of a table, and the number of bits indicating the differential CQI may be 3 bits, 2 bits, or another number of bits. Table 3 is a table showing the mapping relationship between the 3-bit differential CQI and the offset, and Table 4 is a table showing the mapping relationship between the 2-bit differential CQI and the offset.

As shown in Table 3 and Table 4, 0 (000) to 7 (111), or 0 (00) to 3 (11) represents the bit value of the differential CQI, and M _{1 to} M ₈ or M _{1 to} M _4. Is an offset reference value corresponding to each bit value of the differential CQI, and M ₁ <M ₂ <... <M ₈ .

In the present embodiment, preferably, the minimum value (for example, “0”) of the bit value indicating the difference CQI corresponds to a value less than the minimum value (for example, “M ₁ ”) of the plurality of offset reference values, and the difference CQI is set to The maximum value (for example, “7” or “3”) of the indicated bit value corresponds to a value equal to or greater than the maximum value (for example, “M ₈ ” or “M ₄ ”) of the plurality of offset reference values. The present embodiment is not limited to this, and the minimum value and the maximum value of the bit value indicating the difference CQI correspond to the corresponding offset reference value depending on the values of M _{1 to} M ₈ or M _{1 to} M _4. However, the number of intermediate bits having the difference CQI may correspond to a value equal to or less than the corresponding offset reference value. When Table 3 as an example, 0 (000) corresponds to _{M 1,} 7 (111) are corresponding to _{M 8,} 3 (011) corresponds to the value of _{M 4} below, or _{M 4} or more values Ie, 0 → ≦ M ₁ , 7 → ≦ M ₈ , 3 → ≦ M ₄ or ≧ M ₄ .

  In the present embodiment, preferably, when the base station uses different CoMP transmission modes, the terminal apparatus may use a mapping relationship between the differential CQI and the offset having different numbers of bits. For example, when the base station uses the JP CoMP transmission mode, the terminal apparatus uses the mapping relationship between the 3-bit differential CQI and the offset. When the base station uses the CS / CB CoMP transmission mode, the terminal apparatus A mapping relationship between 2-bit differential CQI and offset is used.

In the present embodiment, preferably, when the base station uses different CoMP transmission modes, when the terminal device uses the mapping relationship between the difference CQI and the offset having the same number of bits, the terminal device uses the offset reference values having different values. May be. For example, when the base station uses the CoMP transmission mode of JP and when the base station uses the CoMP transmission mode of CS / CB, both the terminal devices use the mapping relationship between the 3-bit differential CQI and the offset. When the base station uses the JP CoMP transmission mode, M _{1 to} M ₈ are used as a plurality of offset reference values in the mapping relationship between the 3-bit differential CQI and the offset, and the base station performs CS / CB CoMP transmission. When the mode is used, M ₁ ′ to M ₈ ′ are used as a plurality of offset reference values in the mapping relationship between the 3-bit differential CQI and the offset. Preferably, M ₈ ≧ M ₈ ′.

  In this embodiment, preferably, when the base station uses the CoMP transmission mode of JP, the minimum value of the offset reference value in the mapping relationship between the differential CQI and the offset used by the terminal device is 0, 1, or 2. When the base station uses the CS / CB CoMP transmission mode, the minimum value of the offset reference value in the mapping relationship between the differential CQI and the offset used by the terminal apparatus is −1 or 0.

Table 5 shows an example of the mapping relationship between the 3-bit differential CQI and the offset established by the terminal device when the base station uses the JP CoMP transmission mode. Tables 6 and 7 show two examples of the mapping relationship between the 3-bit differential CQI and the offset established by the method of this embodiment when the base station uses the CB / CS CoMP transmission mode. . Tables 6 and 7 show two examples of the mapping relationship between the 2-bit differential CQI and the offset established by the terminal device when the base station uses the CB / CS CoMP transmission mode. .

  According to the method of the present embodiment, the terminal apparatus can establish a mapping relationship between different differential CQIs and offsets according to the CoMP transmission mode, and when the differential CQI needs to be fed back, Since feedback is performed, the overhead of CQI feedback can be reduced, and the throughput of user equipment based on CoMP transmission can be improved.

  As described in the following embodiments, embodiments of the present invention further provide a terminal device. Since the principle of solving the problem of the terminal device is similar to the method of establishing the mapping relationship between the differential CQI and the offset of the terminal device of the first embodiment, the embodiment of the terminal device can refer to the implementation of the method and overlap The description of the part is omitted.

<Example 2>
FIG. 3 is a diagram illustrating a configuration of the terminal device according to the embodiment of the present invention. As illustrated in FIG. 3, the terminal device includes an establishing unit 31.

  The establishing unit 31 determines the number of bits indicating the differential CQI and the mapping relationship so as to perform feedback of the differential CQI based on the mapping relationship between each bit value of the differential CQI and the offset reference value. Here, the plurality of offset reference values corresponding to the bit values in ascending order of the bit values are a plurality of increasing integers.

  In one embodiment, in the mapping relationship between the differential CQI and the offset established by the establishing unit 31, the minimum value of the bit value corresponds to a value equal to or less than the minimum value of a plurality of offset reference values, The maximum value corresponds to a value that is greater than or equal to the maximum value of the plurality of offset reference values. The present embodiment is not limited to this, and the intermediate value of the bit values may correspond to a value that is greater than or less than the corresponding offset reference value.

  In another embodiment, when the CoMP transmission mode used by the base station is different, the number of bits is different in the mapping relationship between the differential CQI established by the establishment unit 31 and the offset. Alternatively, the plurality of offset reference values are different in the mapping relationship between the differential CQI and the offset established by the establishing unit 31.

  In another embodiment, when the CoMP transmission mode used by the base station is the JP transmission mode, the minimum offset reference value is 0, 1 in the mapping relationship between the differential CQI established by the establishing unit 31 and the offset. Or 2 and when the CoMP transmission mode used by the base station is the multipoint CS / CB transmission mode, in the mapping relationship between the differential CQI established by the establishing unit 31 and the offset, the minimum value of the offset reference value is − 1 or 0.

  In another embodiment, when the CoMP transmission mode used by the base station is the JP transmission mode, the maximum offset reference value in the mapping relationship between the differential CQI and the offset established by the establishing unit 31 is used by the base station. When the CoMP transmission mode is the CS / CB transmission mode, it is larger than the maximum offset reference value in the mapping relationship between the differential CQI established by the establishing unit 31 and the offset.

  According to the terminal apparatus of the present embodiment, the terminal apparatus can establish a mapping relationship between different differential CQIs and offsets according to the CoMP transmission mode, and when the differential CQI needs to be fed back, the differential CQI is determined by the mapping relationship. Therefore, the overhead of CQI feedback can be reduced, and the throughput of user equipment based on CoMP transmission can be improved.

<Example 3>
FIG. 4 is a flowchart of a channel quality information feedback method according to an embodiment of the present invention. The method is used for a terminal device in which a CoMP feedback mode is set. As shown in FIG. Includes steps.

  First calculation step 401: Calculate CQI based on non-CoMP transmission and CQI based on CoMP transmission based on the downlink reference signal.

  Here, the downlink reference signal may be CRS (Cell-specific Reference Signal) and / or CSI-RS (Channel State Information-Reference Signal), Other downlink reference signals may be used, and the present embodiment is not limited to this.

  Note that the CQI information of each transmission block based on non-CoMP transmission and the CQI information of each transmission block based on CoMP transmission are quantization signal-to-noise ratios corresponding to the respective received signal equations. It is obtained by calculation using a technique, and the description thereof is omitted here.

  Second calculation step 402: Calculate CQI offset based on CoMP transmission based on CQI based on non-CoMP transmission and CQI based on CoMP transmission.

  Determination step 403: Based on the CQI offset based on the CoMP transmission and the mapping relationship between the differential CQI and the offset established in advance, the differential CQI based on the CoMP transmission is determined. Here, in the mapping relationship between the difference CQI and the offset established in advance, the plurality of offset reference values corresponding to the difference CQI in ascending order of the difference CQI are a plurality of increasing integers.

  Here, the CQI offset based on the calculated CoMP transmission is compared with the mapping relationship between the differential CQI and the offset established in advance to determine the differential CQI based on the CoMP transmission.

  Feedback step 404: CQI based on the non-CoMP transmission and differential CQI based on the CoMP transmission are fed back to the base station.

  In this embodiment, for different CoMP transmission modes, a mapping relationship between different differential CQIs and offsets is established in advance, and the mapping relationship represents a mapping relationship between differential CQIs and offset reference values. When the CQI offset is determined by calculation, the corresponding difference CQI may be determined by comparing the CQI offset with an offset reference value in the pre-established mapping relationship.

  Here, regarding the establishment of the mapping relationship, the first embodiment is referred to, the contents of the first embodiment are incorporated herein, and the description thereof is omitted.

  In one embodiment, when a CQI offset based on CoMP transmission is less than or equal to a minimum value of a plurality of offset reference values, a differential CQI based on CoMP transmission is a minimum difference CQI in a mapping relationship between a differential CQI and an offset established in advance. It is determined to be a value. When the CQI offset based on CoMP transmission is greater than or equal to the maximum value of a plurality of offset reference values, the differential CQI based on CoMP transmission is determined to be the maximum value of the differential CQI in the mapping relationship between the differential CQI and the offset established in advance. .

  In this embodiment, in the mapping relationship between the differential CQI and the offset established in advance, the number of bits indicating the differential CQI may be 3 bits or 2 bits. The mapping relationship between the differential CQI and the offset may be expressed in the form of a table. As described above, Table 3 is a mapping table of 3-bit differential CQI and offset, and Table 4 is a mapping table of 2-bit differential CQI and offset.

In Table 3, M ₁ , M ₂ ,..., M ₈ are offset reference values, the offset reference values M ₁ , M ₂ ,..., M ₈ are integers, and M ₁ <M ₂ < ... <M ₈ . In Table 4, M ₁ , M ₂ ,..., M ₄ are offset reference values, the offset reference values M ₁ , M ₂ ,..., M ₄ are integers, and M ₁ <M ₂ < ... <M ₄ .

Preferably, when the base station uses the CoMP transmission mode of multipoint combining processing (JP), the minimum value of the plurality of offset reference values, that is, M ₁ may be 0, 1, or 2. Table 5 shows a mapping table (that is, mapping relationship) between the 3-bit differential CQI and the offset established in advance according to the embodiment of the present invention when the base station uses the CoMP transmission mode of multipoint combining processing (JP). This is a preferred example.

Preferably, when the base station uses the CoMP transmission mode of multipoint coordinated scheduling / beamforming (CS / CB), the minimum value of the plurality of offset reference values, that is, M ₁ may be −1 or 0. Tables 6 and 7 show that when the base station uses the CoMP transmission mode of multipoint coordinated scheduling / beamforming (CS / CB), the difference between the 3-bit differential CQI and the offset established in advance according to the embodiment of the present invention. It is a suitable example of a mapping table. Tables 8 and 9 show that when the base station uses the CoMP transmission mode of multipoint coordinated scheduling / beamforming (CS / CB), the difference between the 2-bit differential CQI and the offset established in advance according to the embodiment of the present invention. It is a suitable example of a mapping table.

  In this embodiment, mapping relationships between different differential CQIs and offsets may be established in advance according to different CoMP transmission modes. For example, mapping relationships having the same number of bits and different offset reference values may be established in advance, or mapping relationships having different numbers of bits may be established in advance.

For mapping relationships with the same number of pre-established bits and different offset reference values, the maximum values of the plurality of offset reference values in the mapping relationship are different. Preferably, the maximum value of the plurality of offset reference values when the base station uses the multipoint JP CoMP transmission mode is the maximum value of the plurality of offset reference values when the base station is the multipoint CS / CB CoMP transmission mode. Bigger than. For example, when the base station uses the CoMP transmission mode of multipoint JP and the CoMP transmission mode of multipoint CS / CB, when selecting the mapping relationship between the 3-bit differential CQI and the offset, M ₈ (JP) ≧ M ₈ (CS / CB).

  For example, when the base station uses the CoMP transmission mode of multipoint JP, the mapping relationship between the 3-bit differential CQI and the offset may be established in advance. When the multipoint CS / CB CoMP transmission mode is used, a mapping relationship between a 2-bit differential CQI and an offset may be established in advance.

  In this embodiment, different mapping relationships may be established in advance for the same CoMP transmission mode and different ranks. For example, when the base station uses the CoMP transmission mode of multipoint CS / CB, when rank = 1, the mapping relationship between the differential CQI and the offset shown in Table 8 can be established in advance by the method according to the first embodiment. Well, when rank = 2, the mapping relationship between the differential CQI and the offset shown in Table 9 may be established in advance by the method according to the first embodiment.

  In the present embodiment, the number of transmission blocks that feed back CQI differs depending on the values of different ranks fed back by the terminal device.

  When the rank fed back from the terminal apparatus is 1, in step 404, when only CQI based on CoMP transmission and CQI based on non-CoMP transmission of one transmission block need to be fed back, one transmission is performed in step 401. Only CQI based on block CoMP transmission and CQI based on non-CoMP transmission are calculated, and the CQI offset based on CoMP transmission calculated in step 402 is the difference between the CQI index based on CoMP transmission and the CQI index based on non-CoMP transmission. It is.

  When the rank fed back from the terminal apparatus is 2 or more, in step 404, when it is necessary to feed back the differential CQI based on the CoMP transmission of the two transmission blocks and the CQI based on the non-CoMP transmission, Calculate CQI based on CoMP transmission of transmission block and CQI based on non-CoMP transmission, calculate CQI offset based on CoMP transmission of two transmission blocks in step 402, and non-CoMP transmission of two transmission blocks in step 404 And CQI based on CoMP and differential CQI based on CoMP transmission are fed back. In one embodiment, the CQI offset based on CoMP transmission of each transmission block is the difference between the CQI index based on CoMP transmission of the transmission block and the CQI index based on non-CoMP transmission of the transmission block. In another embodiment, the CQI offset based on the CoMP transmission of the first transmission block is the difference between the CQI index based on the CoMP transmission of the first transmission block and the CQI index based on the non-CoMP transmission of the first transmission block. The CQI offset based on the CoMP transmission of the second transmission block is the difference between the CQI index based on the CoMP transmission of the first transmission block and the CQI index based on the CoMP transmission of the second transmission block.

  According to the terminal device according to the present embodiment, in which the user equipment feeds back channel quality information in the cooperative multipoint (CoMP) transmission mode, the terminal device performs single point (non-CoMP) transmission based on the downlink reference signal. Channel quality information and channel quality information of cooperative multipoint (CoMP) transmission are estimated, and the quantized channel quality information is fed back to the base station based on a previously established mapping relationship. The base station can dynamically schedule single point transmission or coordinated multipoint transmission to provide service to the user equipment based on the channel quality information fed back by the terminal device. The method can reduce the overhead of CQI feedback by designing rational CQI feedback for different performance improvements by different CoMP transmission technologies, and can improve the throughput of user equipment based on CoMP transmission.

  As described in Example 4 below, an embodiment of the present invention further provides a terminal device. Since the principle of solving the problem of the terminal device is similar to the channel quality information feedback method of the terminal device of the third embodiment, the embodiment of the terminal device can refer to the implementation of the method, and the description of the overlapping parts is omitted. It is said.

<Example 4>
FIG. 5 is a diagram illustrating a configuration of another terminal apparatus according to the embodiment of the present invention, and the terminal apparatus is a terminal apparatus set with a CoMP feedback mode. As illustrated in FIG. 5, the terminal device includes a first calculation unit 51, a second calculation unit 52, a determination unit 53, and a feedback unit 54.

  The first calculator 51 calculates CQI based on non-CoMP transmission and CQI based on CoMP transmission based on the downlink reference signal.

  The second calculator 52 calculates a CQI offset based on the CoMP transmission based on the CQI based on the non-CoMP transmission calculated by the first calculator 51 and the CQI based on the CoMP transmission.

  The determination unit 53 determines the differential CQI based on CoMP transmission based on the CQI offset based on the CoMP transmission calculated by the second calculation unit 52 and the mapping relationship between the differential CQI and the offset established in advance. Here, in the mapping relationship between the difference CQI and the offset established in advance, the plurality of offset reference values corresponding to the difference CQI in ascending order of the difference CQI are a plurality of increasing integers.

  The feedback unit 54 feeds back the CQI based on the non-CoMP transmission calculated by the first calculation unit 53 and the differential CQI based on the CoMP transmission determined by the determination unit 53 to the base station.

  In one embodiment, the determination unit 53 includes a comparison module 531 and a determination module 532.

  The comparison module 531 determines the difference between the CQI offset based on the CoMP transmission calculated by the second calculation unit 52 and the difference CQI and the offset established in advance so as to determine the difference CQI corresponding to the CQI offset based on the CoMP transmission. The offset reference value in the mapping relationship is compared.

  In one embodiment, as a comparison result in the comparison module 531 by the determination module 532, if the CQI offset based on CoMP transmission is less than or equal to the minimum value of a plurality of offset reference values, a difference CQI based on CoMP transmission is established in advance. When it is determined that the difference CQI is the minimum value in the mapping relationship between the CQI and the offset, and the CQI offset based on the CoMP transmission is equal to or larger than the maximum value of a plurality of offset reference values, the differential CQI based on the CoMP transmission is established in advance. It is determined to be the maximum value of the difference CQI in the mapping relationship between the difference CQI and the offset. The above description is merely illustrative, and embodiments of the present invention are not limited thereto. If the intermediate value of the difference CQI bit value in the mapping relationship is greater than or less than the corresponding offset reference value, it must be compared with the corresponding numerical value.

  In one embodiment, the number of bits indicating the difference CQI in the mapping relationship between the difference CQI and the offset is 3 bits. In another embodiment, the number of bits indicating the difference CQI in the mapping relationship between the difference CQI and the offset is 2 bits.

  In one embodiment, according to different CoMP transmission modes, a plurality of offset reference values in the mapping relationship between the differential CQI and the offset established in advance by the terminal device are different, or the differential CQI established in advance by the terminal device and The number of bits indicating the difference CQI in the mapping relationship with the offset is different.

  In one embodiment, when the base station uses the CoMP transmission mode of multipoint JP, the minimum value of the plurality of offset reference values is 0, 1 in the mapping relationship between the differential CQI and the offset established in advance in the terminal device. Or 2. In another embodiment, when the base station uses the CoMP transmission mode of multipoint CS / CB, the minimum value of the plurality of offset reference values in the mapping relationship between the differential CQI and the offset established in advance by the terminal device is: -1 or 0.

  In one embodiment, when the base station uses the CoMP transmission mode of multipoint JP, the maximum value of the plurality of offset reference values in the mapping relationship between the differential CQI and the offset established in advance by the terminal device is the base station Is larger than the maximum value of the plurality of offset reference values in the mapping relationship between the differential CQI and the offset established in advance in the terminal device in the multipoint CS / CB CoMP transmission mode.

  In one embodiment, when the rank fed back from the terminal apparatus is 1, the CQI offset based on the CoMP transmission calculated by the second calculator 52 is the CQI index based on the CoMP transmission and the CQI based on the non-CoMP transmission. It is the difference from the index.

  In one embodiment, when the rank fed back from the terminal device is 2 or more, the first calculation unit 51 calculates CQI based on non-CoMP transmission and CQI based on CoMP transmission of two transmission blocks, and The second calculation unit 52 calculates the CQI offset based on the CoMP transmission of the two transmission blocks, and the CQI offset based on the CoMP transmission of each transmission block includes the CQI index based on the CoMP transmission of the transmission block and the non-transmission of the transmission block. The feedback unit 54 feeds back a CQI based on non-CoMP transmission of two transmission blocks and a differential CQI based on CoMP transmission.

  In another embodiment, when the rank fed back from the terminal device is 2 or more, the first calculation unit 51 calculates CQI based on non-CoMP transmission and CQI based on CoMP transmission of two transmission blocks, and The second calculator 52 calculates a CQI offset based on the CoMP transmission of the two transmission blocks, and the CQI offset based on the CoMP transmission of the first transmission block is a CQI index based on the CoMP transmission of the first transmission block. The difference between the CQI index based on the non-CoMP transmission of the first transmission block and the CQI offset based on the CoMP transmission of the second transmission block is the CQI index based on the CoMP transmission of the first transmission block and the second transmission. Difference from CQI index based on block CoMP transmission Ri, a feedback unit 54 feeds back the CQI of two transport blocks based on the differential CQI and non-CoMP transmission two transport blocks based on the CoMP transmission.

  A terminal apparatus according to an embodiment of the present invention can reduce overhead of CQI feedback by designing rational CQI feedback for different performance improvements by different CoMP transmission technologies, and can reduce the overhead of user equipment based on CoMP transmission. Throughput can be improved.

  The embodiment of the present invention further provides a computer-readable program, and when the computer-readable program executes the program in the terminal device, the computer executes the difference CQI and the offset described in the first embodiment. The terminal device is caused to execute a mapping relationship establishing method.

  The embodiment of the present invention further provides a storage medium for storing a computer-readable program, and the computer-readable program stores the mapping relationship between the differential CQI and the offset described in the first embodiment in the computer. Is executed in the terminal device.

  The embodiment of the present invention further provides a computer-readable program, and when the computer-readable program executes the program in the terminal device, the computer feeds the channel quality information feedback method according to the third embodiment. Is executed in the terminal device.

  The embodiment of the present invention further provides a storage medium for storing a computer readable program, and the computer readable program executes the channel quality information feedback method described in the third embodiment in a terminal device. Let

  The above apparatus and method of the present invention may be realized by hardware, or may be realized by combining hardware and software. The present invention relates to a computer-readable program. When the program is executed by a logic unit, the logic unit realizes the above-described apparatus or configuration requirements, or the logic unit realizes various methods or steps described above. Can be made. The present invention relates to a storage medium for storing the above program, such as a hard disk, a disk, an optical disk, a DVD, a flash memory, and the like.

  Although the present invention has been described above with reference to specific embodiments, the above description is merely illustrative and does not limit the scope of protection of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and principle of the present invention, and these changes and modifications are also within the scope of the present invention.

Claims (20)

A CQI feedback method used in a terminal device set in a cooperative multipoint (CoMP) feedback mode,
A first calculation step of calculating channel quality information (CQI) based on non-CoMP transmission and CQI based on CoMP transmission based on a downlink reference signal;
A second calculation step of calculating a CQI offset based on CoMP transmission based on CQI based on non-CoMP transmission and CQI based on CoMP transmission;
A determination step of determining a differential CQI based on CoMP transmission based on a mapping relationship between the CQI offset based on the CoMP transmission and a previously established differential CQI and offset, the differential CQI and the offset established in advance; In the mapping relationship, a plurality of offset reference values corresponding to the difference CQI in ascending order of the difference CQI are a plurality of increasing integers;
A feedback step of feeding back the CQI based on the non-CoMP transmission and the differential CQI based on the CoMP transmission to a base station. In the determining step,
Comparing the CQI offset based on the CoMP transmission with an offset reference value in the mapping relationship between the previously established differential CQI and offset so as to determine a differential CQI corresponding to the CQI offset based on the CoMP transmission. Item 6. The channel quality information feedback method according to Item 1 . In mapping relationship between the pre-established differential CQI offset, the number of bits indicating the differential CQI is 3 bits or 2 bits, the feedback method of the channel quality information according to claim 1. In accordance with different CoMP transmission modes, a plurality of offset reference values in the mapping relationship between the differential CQI and the offset established in advance are different, or the differential CQI in the mapping relationship between the differential CQI and the offset established in advance is indicated. the number of bits different feedback method of the channel quality information according to claim 1. When the base station uses a CoMP transmission mode of multipoint combining processing (JP), the maximum value of the plurality of offset reference values is the CoMP transmission mode of multipoint coordinated scheduling or beamforming (CS / CB) by the base station. 2. The channel quality information feedback method according to claim 1 , wherein the channel quality information is larger than a maximum value of the plurality of offset reference values in the case of. When the base station uses the CoMP transmission mode of multipoint JP, the minimum value of the plurality of offset reference values is 0, 1 or 2,
2. The channel quality information feedback method according to claim 1 , wherein, when the base station uses a multipoint CS / CB CoMP transmission mode, a minimum value of the plurality of offset reference values is −1 or 0. 3. When the rank fed back from the terminal device is 1, in the second calculation step, the CQI offset based on CoMP transmission is a difference between a CQI index based on CoMP transmission and a CQI index based on non-CoMP transmission. Item 6. The channel quality information feedback method according to Item 1 . When the rank fed back from the terminal device is 2 or more,
In the first calculation step, CQI based on non-CoMP transmission and CQI based on CoMP transmission of two transmission blocks are calculated,
In the second calculation step, a CQI offset based on CoMP transmission of two transmission blocks is calculated, and a CQI offset based on CoMP transmission of each transmission block is calculated based on a CQI index based on the CoMP transmission of the transmission block and the transmission block. The difference from the CQI index based on non-CoMP transmission,
2. The channel quality information feedback method according to claim 1 , wherein, in the feedback step, the terminal apparatus feeds back CQI based on non-CoMP transmission of two transmission blocks and differential CQI based on CoMP transmission. When the rank fed back from the terminal device is 2 or more,
In the first calculation step, CQI based on non-CoMP transmission and CQI based on CoMP transmission of two transmission blocks are calculated,
In the second calculation step, a CQI offset based on the CoMP transmission of the two transmission blocks is calculated, and the CQI offset based on the CoMP transmission of the first transmission block is a CQI index based on the CoMP transmission of the first transmission block. The difference between the CQI index based on the non-CoMP transmission of the first transmission block and the CQI offset based on the CoMP transmission of the second transmission block is the CQI index based on the CoMP transmission of the first transmission block and the second transmission. The difference from the CQI index based on the CoMP transmission of the block,
2. The channel quality information feedback method according to claim 1 , wherein, in the feedback step, the terminal apparatus feeds back a differential CQI of two transmission blocks based on CoMP transmission and a CQI of two transmission blocks based on non-CoMP transmission. A terminal device set in the feedback mode of CoMP,
First calculating means for calculating CQI based on non-CoMP transmission and CQI based on CoMP transmission based on a downlink reference signal;
Second calculation means for calculating a CQI offset based on CoMP transmission based on CQI based on non-CoMP transmission calculated by the first calculation means and CQI based on CoMP transmission;
Determining means for determining a differential CQI based on CoMP transmission based on a mapping relationship between a CQI offset calculated based on the CoMP transmission calculated by the second calculating means and a differential CQI and offset established in advance; In the mapping relationship between the differential CQI and the offset established in advance, the plurality of offset reference values corresponding to the differential CQI in ascending order of the differential CQI are a plurality of increasing integers;
And a feedback unit that feeds back a CQI based on non-CoMP transmission calculated by the first calculation unit and a differential CQI based on CoMP transmission determined by the determination unit to a base station. The determining means includes
In the mapping relationship between the CQI offset based on the CoMP transmission calculated by the second calculating means and the previously established differential CQI and offset so as to determine the differential CQI corresponding to the CQI offset based on the CoMP transmission The terminal device according to claim 10 , further comprising a comparison module that compares the offset reference value. The terminal device according to claim 10 , wherein the number of bits indicating the differential CQI is 3 bits or 2 bits in a mapping relationship between the differential CQI and the offset established in advance in the terminal device. The terminal device uses a mapping relationship between different offset CQIs and offsets having different offset reference values according to different CoMP transmission modes, or between differently established bit CQIs and offsets having different bit numbers. The terminal device according to claim 10 , wherein a mapping relationship is used. When the base station uses the CoMP transmission mode of multipoint combining processing (JP), the maximum value of a plurality of offset reference values in the mapping relationship between the differential CQI and the offset established in advance by the terminal device is the base station When the station is in the CoMP transmission mode of multipoint coordinated scheduling or beamforming (CS / CB), the maximum difference among the offset reference values in the mapping relationship between the differential CQI and the offset established in advance by the terminal device The terminal device according to claim 10, which is large. When the base station uses the CoMP transmission mode of multipoint JP, the minimum value of the plurality of offset reference values is 0, 1, or 2 in the mapping relationship between the differential CQI and the offset established in advance in the terminal device. ,
When the base station uses the CoMP transmission mode of multipoint CS / CB, the minimum value of the plurality of offset reference values is −1 or 0 in the mapping relationship between the differential CQI and the offset established in advance in the terminal device. The terminal device according to claim 10 . When the rank fed back from the terminal device is 1, the CQI offset based on the CoMP transmission calculated by the second calculating unit is a difference between the CQI index based on the CoMP transmission and the CQI index based on the non-CoMP transmission. The terminal device according to claim 10 . When the rank fed back from the terminal device is 2 or more,
The first calculating means calculates CQI based on non-CoMP transmission and CQI based on CoMP transmission of two transmission blocks;
The second calculating means calculates a CQI offset based on the CoMP transmission of two transmission blocks, and the CQI offset based on the CoMP transmission of each transmission block includes a CQI index based on the CoMP transmission of the transmission block and the transmission block. The difference from the CQI index based on non-CoMP transmission,
The terminal apparatus according to claim 10 , wherein the feedback means feeds back a CQI based on non-CoMP transmission of two transmission blocks and a differential CQI based on CoMP transmission. When the rank fed back from the terminal device is 2 or more,
The first calculating means calculates CQI based on non-CoMP transmission and CQI based on CoMP transmission of two transmission blocks;
The second calculating means calculates a CQI offset based on the CoMP transmission of the two transmission blocks, and the CQI offset based on the CoMP transmission of the first transmission block is a CQI index based on the CoMP transmission of the first transmission block. The difference between the CQI index based on the non-CoMP transmission of the first transmission block and the CQI offset based on the CoMP transmission of the second transmission block is the CQI index based on the CoMP transmission of the first transmission block and the second transmission. The difference from the CQI index based on the CoMP transmission of the block,
The terminal apparatus according to claim 10 , wherein the feedback section feeds back a differential CQI of two transmission blocks based on CoMP transmission and a CQI of two transmission blocks based on non-CoMP transmission. A computer-readable program for causing a computer to execute the channel quality information feedback method according to any one of claims 1 to 9 on the terminal device when the terminal device executes the program. A storage medium for storing a computer-readable program for causing a computer to execute the channel quality information feedback method according to any one of claims 1 to 9 .

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